Numerous surgical instruments are known in the prior art for performing various surgical operations on small and delicate body parts. Ophthalmological instruments in particular are required to be very small while providing proper hand control over the instrument to effectively perform the surgical operation and to prevent damage to the tissue.
In microsurgery, such as in the eye, it is necessary to have an instrument which can enter the cavity of the eye and be manipulated easily within the eye at various angles with respect to the opening or incision and the operating surface without having to enlarge the opening Numerous devices have been proposed which have met with limited success for various reasons. Examples of these previous devices include finger operated scissors and forceps. Various surgical instruments have forceps or scissors which are not rotatably adjustable with respect to the handle and actuating mechanism. These devices are difficult to use at some angles with respect to the operating surface since the entire instrument must be rotated in the hand. Other surgical instruments which allow rotational movement of the instrument tip with respect to the handle do not lend themselves to easy rotational adjustment during use in surgery. Examples of these types of surgical instruments are disclosed generally in U.S. Pat. No. 4,258,716 to Sutherland, U.S. Pat. No. 4,955,887 to Zirm and U.S. Pat. No. 5,370,658 to Scheller et al.
A typical disadvantage of the previous surgical instruments is that the instruments can be difficult to manipulate in various rotational positions with respect to the plane of the actuating levers and fingers. To overcome this disadvantage, surgical instruments have been produced which have a rounded surface to enable the instrument to be rotated slightly in the surgeon's hand. These devices do not always provide proper or efficient actuation of the instrument following gross rotation within the handgrip. In addition, these surgical instruments typically have gripping surfaces which are wider at the distal end of the tool tip. Ophthalmological instruments, which are required to be used in a near vertical position, are difficult to grip with this type of handle. The inverted conical shape of the gripping surfaces allow the instrument to slip downwardly from the surgeon's fingers into the eye which can cause further damage to the eye. Although the surgical instruments can be provided with a slip resistant surface, it is difficult for the surgeon to grip the instrument when the instrument is covered with blood, mucus or other fluids encountered during surgery.
Another disadvantage of some of the prior surgical instruments is the ability of the actuating levers to pinch the surgeon's fingers or surgical gloves during actuation. This ultimately interferes with the surgeon's ability to operate the instrument and perform the surgical operation.
A further disadvantage of the previous surgical instruments is the actuating levers being positioned far from the tip of the instrument. The greater the distance the surgeon's fingers from the instrument tip, the greater any unintentional motions of the surgeon's fingers are amplified at the instrument tip. These prior devices do not permit the surgeon to grip the instrument sufficiently close to the instrument tip to minimize the motion amplification at the tip.
Accordingly, there is a continuing need in the art for surgical instruments which overcome the above-noted disadvantages of the prior surgical instruments.